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I found this part broken on my recently acquired 2007 S60. It is a valve in front of the air filter box and has 3 hoses, some going to the intake manifold. I disconnected the electrical plug and cannot find a part number.
electric vacuum pump switch. Provides vaccum for power brake booster when engine vacuum is too low (cold starts, especially at altitude).
The electric switch end looks to be broken off that one. The brown connector would go on a two wire switch.
Thank you! I can now search for a replacement part. I see a metal can lower down with hoses and electrical connections which I assume is the vacuum pump.
I have the electrical switch end in my pocket. It was broken off the valve and was wrapped around another hose down low with the wiring attached to the switch end, as if to hide it. Thats why I need a replacement.
I’ve driven it about 120 miles, and did not notice a lack of power brakes. It is cold here in Boulder, CO. (28 degrees now) and we are above 5,000 feet altitude.
If you wait about 20 seconds from starting, your engine will come down off high idle, and you probably will never notice the lack of the vacuum pump.
jimmy will fix this if wrong, but my recollection is the intake CVVT gets massively advanced to give gobs of air in to reduce cold start emissions, the idle is elevated to keep it running, untll the excess start fuel is burned off
All that air makes manifold vacuum, and thus brake vacuum, in short supply.
The exhaust cam is advanced to allow still burning fuel to exit to warm catalyst and to eliminate the need for the previously used exhaust air injection pump.
I am a crank and go person so I could feel hard brakes at low altitude in cold weather when I started and selected a gear. The time when there is little vacuum is in the first minute when cam and ignition timing together with greater throttle opening are diminishing vacuum.
Jumper the two wire connector to see if the vacuum pump is OK.
I did as Jimmy suggested. I jumpered the connector and started the car. Then I listened to see if I could hear the pump running (heard nothing) and then felt the top of the vacuum pump to see if I could feel the pump running (felt nothing). I made connection and released connection several times in case my jumpers were not making contact but again, nothing.
I then looked in the fuse box to see if there was a vacuum pump fuse but didn’t see any. Is there a relay and fuse, and if so, where are they located?
I believe the design of this brake boost vacuum could be better. If there is a leak in a hose, a failure in the brake booster, a failure of the vacuum operated electrical switch, the pump runs continuously and burns out. If I were to redesign this, i would limit 1) the % cycle time the pump runs during warm up (e.g. 5 seconds on 5 seconds off), the total time the pump runs after cold start (e.g. 5 minutes). and then throw a code if the system sees low vacuum and wants to run even more identifying a possible failure with the switch, hose, or brake booster. Protect the vacuum pump!